President Barack Obama said the alleged mass chemical attack in Syria “is clearly a big event of grave concern,” he told CNN in an interview aired Friday morning. But the President was hesitant to get the U.S. more involved. Citing the ongoing human and financial burdens the U.S. still faces in Afghanistan, he was unwilling to “get involved with everything immediately” and “drawn into very expensive, difficult, costly interventions that actually breed more resentment in the region.”

Two years ago this month, Obama called for the ouster of Syrian strongman Bashar Assad. A year ago, Obama drew what he called a “red line” saying the use of chemical weapons would change his “calculus” on the conflict, which has claimed more than 100,000 lives over the last two and a half years. Syrian opposition groups say this red line has now been crossed with this one attack Wednesday morning claiming as many as 1,300 lives in the eastern suburbs of Damascus.

Now that that moment seems to have arrived, though, the President is hedging. “There is no doubt that when you start seeing chemical weapons used on a large scale — and, again, we’re still gathering information about this particular event, but it is very troublesome,” Obama said. The President called on the United Nations to investigate the attack. But said he remained leery of entering a fresh conflict abroad without a UN mandate. “If the U.S. goes in and attacks another country without a U.N. mandate and without clear evidence that can be presented, then there are questions in terms of whether international law supports it, do we have the coalition to make it work, and, you know, those are considerations that we have to take into account,” Obama told CNN.

Such a mandate remains highly unlikely. Moscow remains a close ally to the Assad regime and has vetoed all previous attempts in the UN Security Council to pass a resolution using force. Russian officials have accused the Syrian opposition of staging the purported chemical attack against their own population to gain international sympathy.

U.S. officials met Thursday for more than three hours at the White House trying to come up with an appropriate response to the attack, if it’s proven true, according to the New York Times. The actions on the table ranged from a cruise missile attack to an aerial bombing of regime strongholds in Syria, though the officials ended the meeting with no decision made, the paper said.